Some targets may add required passes via
TargetMachine::registerPassBuilderCallbacks(). We need to run those even
under -O0. As an example, BPFTargetMachine adds
BPFAbstractMemberAccessPass, a required pass.
This also allows us to clean up BackendUtil.cpp (and out-of-tree Rust
usage of the NPM) by allowing us to share added passes like coroutines
and sanitizers between -O0 and other optimization levels.
Tests are a continuation of those added in
https://reviews.llvm.org/D89083.
In order to prevent TargetMachines from adding unnecessary optimization
passes at -O0, TargetMachine::registerPassBuilderCallbacks() will be
changed to take an OptimizationLevel, but that will be done separately.
Reviewed By: asbirlea
Differential Revision: https://reviews.llvm.org/D89158
8a12301bab